Sectional metal pole



(No Model.)

J. H. CUNNINGHAM.

SEUTIONAL METAL POLE.

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.IOIIN H. CUNNINGHAM, CF CHELSEA, MASSACHUSETTS.

SECTIONAL Ni ETAL PO LE.

SPECIFICATION forming part of Letters Patent No. 408,379, dated August 6, 1889.

Application filed March Z8, 1889. Serial No. 304,489. (No model.)

.To @ZZ whom it may concern.-

Be it known that I, JOHN H. CUNNINGHAM, of Chelsea, in the county of Suffolk and State of Massachusetts, a citizen of the United States, have invented a new and useful Improvement in Sectional Metal Poles, of which the following' is a full, clear, and exact description, reference being had to the accompanyil'lg drawings, forming a part of this specification, in explaining its nature.

It is desirable that hollow metal poles shall be built in sections, and that the various sections be united in a manner to economize the use of metal and insure proper strength at the joints; and my invention is designed to produce these results, as well as certain other improvements, which will hereinafter be indicated.

In the drawings, Figure l is a view in elevation of the pole; Fig. 2, a view in vertical section, enlarged, of the joint between two section; and Figs. 3 and 4i represent modified forms, to which reference is hereinafter made.

The hollow sections of the pole may be of cast or wrought iron, or both. In practicing the invention I employ as a base-piece the section A, which has a broad base a, by which it is suitably7 anchored in the ground, or which is adapted to be secured in place in any other manner. I forni at the upper end of this section an interior screw-thread a and an exterior screw-thread a2, and I then screw into the end of the pipe the next section B, which has formed upon its lower end the exterior screw-thread h, which ts the interior screw-thread a', andv I screw upon the exterior thread a2 of the pipe the couplingsleeve C. This sleeve has a screw-thread c to fit the said exterior thread a2, and a shoulder c', adapted to rest or come in contact with the upper end of the section A, and a comparatively long sleeve' c2 of a bore to receive the section B. The sections B and E of the pole are simila-rly constructed and united. In some instances, to obtain a tight tit between the section 2 of the sleeve and the end of the section which it receives, molten lead or other similar metal may be poured into the space between the two, although generally it is intended that the sleeve shall not have what would be termed a very 4 loose Iii. If desired, the pole may be stifte'ned by being filled with sand, cement, orother material, or the sections of the pipe applied either during` the manufacture of the pipe or tube or subsequently, (see Fig. 4;) or there may be used Aa smaller pipe or rod in the center of the post and stiff and will not sag, sway, or break at 7o the joint when under strain.

Of course the unthreaded portion of the coupling, which I have termed the sleevc,7 must be of considerable extent, in order to brace and properly support the base of the next section in order, and to prevent the pipe from breaking oft at the upper end of the screw-thread, the object of the sleeve being to extend the supporting-points of the lower section of the pipe considerably above the upper end of the threaded portion of the upper or next section in order.

It is preferable that the sleeve C be made quite thick, and it can be formed by casting, l

Having thus fully described my invention,

I claim and desire to secure by Letters Patent of the United States-y l. As an improved article of manufacture, a hollow metal pole made of two or more sections, which are united by screwing one into the other and bya coupling screwed upon the end ot one and provided with a long sleeve to embrace or receive the end of the other, substantially as described.

' 2. The combination ot the pipe or tube, having at its upper end an interior thread c1.' and an'exterior a2, with the pipe or tube B, having` the exterior thread I) to lit the interior thread of the section A, the sleeve C, having the interior thread c to lit the exterior thread roo 0,2 of lche section A, and Jche long section c2 of a size to receive and sustain the lower part of the said section B, Substantially as described.

brace or receive the end of the other, and the 1o cavity of which sections is `packed or lled with a Substance of a stifenng character, snbstantiail y as described.

. JOHN H. CUNNINGHAM.

In presence of- F. F. RAYMOND, 2d, J. M. DoLAN. 

